My wife has asked me to paint the living room (it's Christmas, in-laws coming). She chose a colour (Dulux - Tuscan Terracotta). I went to the local trade counter and asked them to run up 10 litres using Johnstone's Covaplus (vinyl matt emulsion), which they did. The problem is that a fair amount of (red) dye seems to have got stuck behind the lip inside the tin - it started streaking down the sides, so I remixed it. But it started coming down again a few minutes later. As it's the first of two coats, it's not a problem but it will be tomorrow when I give it a final coat - there are some red patches on the wall. Apart from going back and getting them to shake the tin again, is there a reasonable method of dealing with this? I was thinking of storing the tin upside down overnight (with the lid on, obviously) and mixing again. Any suggestions welcome.